Chapter 9: Problem 39
Assume that electricity costs 15 cents per kilowatthour. Calculate the monthly cost of operating each of the following: a. a \(100-\mathrm{W}\) light bulb, \(5 \mathrm{~h} /\) day b. a \(600-\mathrm{W}\) refrigerator, \(24 \mathrm{~h} /\) day c. a \(12,000-\mathrm{W}\) electric range, \(1 \mathrm{~h} /\) day d. a \(1000-\mathrm{W}\) toaster, \(10 \mathrm{~min} /\) day
Short Answer
Step by step solution
Convert to kilowatt-hours
Calculate cost for the 100-W light bulb
Calculate cost for the 600-W refrigerator
Calculate cost for the 12,000-W electric range
Calculate cost for the 1000-W toaster
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Kilowatt-hour
To calculate kilowatt-hours for an appliance, you need to know two things: the power rating of the appliance (in watts or kilowatts) and how long the appliance is operated. For instance:
- For a device rated at 100 watts operating for 2 hours: Consumption is (100 watts/1000) x 2 hours = 0.2 kWh.
- For a device rated at 50 watts operating for 4 hours: Consumption is (50 watts/1000) x 4 hours = 0.2 kWh.
Energy Consumption
- A high-wattage air conditioner running for several hours a day will consume more energy than a low-wattage fan used for the same duration.
- Similarly, an appliance that is only used occasionally will contribute less to your monthly energy consumption than one that is used daily.
Electric Appliance Usage
For example, using a high-powered electric range for cooking might seem like a brief daily activity, but due to its high wattage, even short usage can lead to significant energy consumption.
Energy-Saving Tips
To reduce the usage cost, consider:- Limiting the use of high-wattage appliances.
- Opting for energy-efficient models when purchasing new appliances.
- Unplugging appliances when they're not in use to avoid 'phantom' energy usage.